1. Field of the Invention
The present invention relates to a method of searching for images.
2. Description of the Prior Art
Techniques have been derived for indexing and searching textual information items, or at least items having some textual content. An example of such a technique is to generate feature data from the textual item (e.g. word distribution) and to allow comparisons between items to be made on the basis of a comparison of the feature data.
With image items, however, few useful techniques have been proposed.
One simple technique is to associate some text with an image. This could be as simple as a title, or could involve more detailed “metadata” such as a paragraph of description, a schedule of items or people in the image, a time of capture of the image, a schedule of those involved in its capture, and so on. Text-based searching techniques can then be used to identify similar images. But of course, providing accurate and useful metadata is time-consuming, expensive and is subjective in respect of the user who generates the metadata.
Other techniques establish feature data based on properties of the images themselves. These might include colour properties, texture properties and the like. But this is also limited because two images, which to a human observer represent the same thing, may have very different image properties. For example, a pair of images of a particular person might have very different image properties because the image backgrounds are different.
It is the aim of the present invention to address these problems.